Starch is a complex carbohydrate composed of two types of polysaccharide molecules, amylose, a mostly linear and flexible polymer of D-anhydroglucose units that are linked by alpha-1,4-D-glucosidic bonds, and amylopectin, a branched polymer of linear chains that are linked by alpha-1,6-D-glucosidic bonds.
Research literature indicates that starches high in fiber and/or resistant starch may have numerous beneficial effects, including colonic health and a reduced caloric value. In addition, the starches may provide reduced meal carbohydrates, reduced glycemic and insulimic responses, impact satiety and contribute to sustained energy release, weight management, control of hypoglycemia, hyperglycemia, impaired glucose regulation, insulin resistance syndrome, type II diabetes mellitus, and improved athletic performance, mental concentration and memory.
It is known that certain starch processing operations including chemical, enzymatic, and physical modifications, may increase the dietary fiber content of starch, such as crosslinking with sodium trimetaphosphate or with a combination of sodium trimetaphosphate and sodium tripolyphosphate. Crosslinking with such reagents are known in the art. However, the crosslinking reaction is not efficient. Many skilled artisans increase the amount of reagent in order to drive the reaction and produce a starch with a high level of bound phosphorus. Unfortunately, this results in high levels of unused reagents in the effluent.
Surprisingly, it has now been discovered that chemically crosslinking starch with sodium trimetaphosphate or a combination of sodium trimetaphosphate and sodium tripolyphosphate may be made more efficient by maintaining the pH at a level of 11.5 to 12.0 during the reaction. This increased efficiency may allow the skilled artisan to use less reagent and lower the level of reactants in the effluent.